delete marker checking taking too long

[shakeebshams]

When checking if a received message has a delete marker, it doesn't respond(within 5s) which results in very slow relay correspondence and a 503 on twilio's side (because it didn't receive a response fast enough). possibly change the res.sendStatus function to call before the delete marker checking has been made (this would fix the 503 from twilio). To fix the slow retrieval, maybe store deleted numbers locally in a data structure rather than in an external db. Theoretically much faster response time and thus lower latency throughout the app